Alternative fuels are being certified to be used in aircraft. However, the fire-safety properties of these fuels are unknown. The present work focused on measurements of the lean flammability limits (LFLs) of three alternative aviation fuels including Hydroprocessed Esters and Fatty Acids (HEFA), Synthesized Iso-Paraffins (SIP), and Fischer-Tropsch Iso-Paraffinic Kerosene (FT-IPK). The results were compared to that of conventional petroleum-based Jet A. The results showed that only FT-IPK had higher LFLs than that of Jet A. Additionally, the LFLs of four pure hydrocarbons including n-heptane, iso-octane, n-decane, and n-dodecane were measured, since they are the major components of transportation fuels. The LFLs were within the range of 0.032–0.040 in terms of the fuel-air mass ratio for all four aviation fuels in the temperature range of 350–420 K. Unlike temperature, pressure had minor influence on the lean flammability limit. For all measured samples (pure hydrocarbons and fuels), the lean limit decreases with increasing molecular weight.
Li, P. Vozka, G. Kilaz, L. Qiao, “Lean Flammability Limits of Pure Hydrocarbon Fuels and Alternative Aviation Fuels,” Fire Safety Journal, Vol 108, September 2019 https://doi.org/10.1016/j.firesaf.2019.102851